| Duck hepatitis (DH), which is caused by duck hepatitis virus (DHV), is a highly fatal,contagious and rapidly spreading viral infection disease, and popular in young ducklings,especially the smaller one. Clinical manifestation is opisthotonos, while athological changesmainly are hepatitis and bleeding. The disease distributes in the world, and is currently one ofthe important infectious diseases in the duck industry.The main pathogen is duck hepatitis A virus (DHAV), including the original typeDHAV-1, a type recently isolated in Taiwan (DHAV-2), and a recently described type isolatedin South Korea and China (DHAV-3). A higher similarity in nucleotide sequence andhomology in amino acid sequence has been described between DHAV-2and DHAV-3. In thepresent, the new type of duck hepatitis is one of the most serious problems in China. No crossprotection in serum was observed between the new and the original type. It is impractical tocontrol duck hepatitis by using yolk antibody or attenuated vaccines, which had been used toprevent the classical DHAV-1.Firstly, the study isolates the new duck hepatitis virus in clinical samples，which isidentified by RT-PCR and the animals regression experiments. On the other hand, I produce aduck embryo kidney primary cell culture models. By the virus inoculation experiments andpassaging experiments we detect the virus adaptation in cell and observe lesions in order toanalyze that part of the biological characteristics of the virus.The research shows that the traditional duck hepatitis virus typeⅠproduces lesions onthe duck embryo primary hepatocytes, and the new duck hepatitis virus can’t adapt to thecells and produce cytopathic effect. By analyzing the proliferation of the virus in duck embryoallantoic cavity and the major structural protein，we lay the foundation for the establishment ofpost-rapid enzyme immunoassay diagnostic methods. Combined with its biological character-istics analysis, we provide a theoretical basis for virus prevention. |
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